Refrigeration apparatus



April 18, 1939. L. c. SMITH REFRIGERATION APPARATUS 4 Sheets-Sheet 1Filed Oct. 2, 1936 Lawrence C 501% M K (Rt "11 g i L. C. SMITH April 18,1939.

REFRIGERATION APPARATUS Filed Oct. 2, 1936 Sheets-Sheet 2' lnventorLawrence C 6021M Gttorucp L C. SMITH A ril 18, 1939.

REFR TGERATTON A PPARATUS Filed Oct. 2, 1936 4 Sheets-Sheet 4 InvcntoxiZawrence C5071);

LTHOI'HNI Patented Apr. 18, 1939 UNITED STATES REFRIGERATION APPARATUSLawrence C. Smith, Kenmore, N. Y., assignor to Fodder-s ManufacturingCompany, Inc., Buflalo,

Application October 2,

12 Claims.

This invention relates to refrigeration evaporators applicable incompressor-condenser-ex-' pander systems, and it has particularreference to the provision of refrigerant evaporators having a 5 suctionmanifold and a plurality of tube loops connected thereto, together withinlet means for each of the separate tubes for admitting the refrigerantthereto.

In the devising of refrigerant expanders or 10 evaporators, there hasbeen proposed the so-called dry coil, which essentially is a length ofcontinuous tubing through which refrigerant may flow and evaporate,andalso the flooded header type,

in which a reservoir of liquid refrigerant may flow 15 down into anumber of spaced tubes where evaporation occurs,--the gases forcingtheir way up through the liquid. In flooded evaporators, the

valve or control mechanism may be either within the reservoir, to givethe low side" type of oper- 20 ation, or in an adjacent vessel, to givethe so-called high side float type of control. All of these basicsystems are well known and have been used, and improvements therein havebeen directed toward the devising of suitable arrangements of the 5necessary parts to increase efliciency of operation or reduction of costof the equipment.

According to the present invention, it is proposed to effectconcurrently an increase in thermal efliciency while effecting savingsin cost, by

30 forming the evaporator with a suction header or manifold, from whichexpanded refrigerant may be withdrawn, and connecting thereto a numberof separate refrigerant evaporation loops or ducts, the feed ofrefrigerant to each of these ducts being 35 into the bottom thereof.

The principles of the invention may be readily applied to various typesof evaporators, such as are especially adapted for domesticrefrigerators, ice-makers, air or room coolers, and the like, and

4 hence they may be herein illustrated by reference to a number oftypical examples. As the description thereof proceeds, it will also bemade apparent that these various evaporators themselves possess numerouspoints of novelty and advan- 45 tage, which will be. recognized by theart.

In the drawings:

Fig. 1 is a side elevation of oneembodiment of the inventionparticularly adapted for a domestic 50 refrigerator;

Fig. 2 is a rear elevation thereof; I

Fig. 3 is a section on the line 33 of Fig. 1, particularly showingdetails of the refrigerated shelf;

55 Fig. 4 is an enlarged section on the line 4-4 of those skilled in,

1936, Serial No. 103,700

Fig. 2. showing the duct and feed tube arrangement;

Fig. 5 is an enlarged longitudinal section through the header;

Fig. 6 is an enlarged cross section on the line 5 66 of Fig. 5;

Fig. 7 is a side elevation of a further embodiment showing the inventionapplied to an evaporator of the ice making type;

Fig. 8 is a rear view thereof, drawn on a reduced scale;

Fig. 9 is a section on the line 9-9 of Fig. '7;

Fig. 10 is an enlarged section on the line Iii-I0 of Fig. 8; I

Fig.'11'is a front view of a further embodiment of the invention asapplied to a cooling coil;

Fig. 12 is an enlarged section on the line l2--l2 ,thereof;

Fig. 13 is a similar but further enlarged section; r

Fig. 14 is a side view of an air cooling coil similar to that of Fig.11, but provided with a slightly different feed arrangement;

Fig. 15 is an enlarged section on the line l5--l5 of Fig. 14.

In the first embodiment of the invention (Figs. l-6) an evaporator 20 isformed with a cylindrical outlet header 2| and ducts 22 which are bentto enclose a rectilinear ice tray housing or sleeve 40. The ends 23 ofthe ducts 22 are inserted through holes 24 of the header and securedthereto, as shown in Fig. 6.

The sleeve is divided into two ice tray compartments by a horizontalshelf 25 which is soldered in place and which contains arefrigerant-duct 26. This duct is formed into several loops, the centralloop 21 thereof projecting beyond the rear end of the sleeve 22 (Fig.3), and the terminal portions 28 of the remaining loops being bentupward and inserted in the header 2i. A can covers the backof the sleeveand it contains an opening 3i through which a portion of the centralloop 21 projects. The sleeve is formed with two opposed slots 32 in itsside walls which permit the duct 26 to be inserted through the rear ofthe sleeve during the assembling operation.

Refrigerant is accurately metered to each duct through a manifold orfeed tube 30 which leads to a feed control element such as a high sidefloat or expansion valve 34. "The feed tube 30 is a simple tube of smalldiameter closed'at one end, as indicated by the numeral 35 (Fig. 4), andprovided with spaced ports 36. Each duct 22 is drilled through, asindicated by the numeral 31, and'the manifold tube is threadedtherethrough, so that each port or pair of ports 36 in the tube 30 isdisposed within a duct. The tube is finally soldered to the ducts toprovide a fluid-tight assembly.

to maintain a "back pressure condition y in the tube 30, which effect isobtained by proportioning the total area of the ports so that it isslightly smaller than the cross sectional area of the tube 30.

' ciently accomplished.

I The header 2| is formed of a tubular body 38 having internal beads 33disposed at one end to provide a mounting shoulder for a head disc 39which is soldered in place. of the body is closed .by a head 4 I whichis tapped to receive a suction conduit 42' leading tothe compressor orsuction side of the refrigeration system (not shown). An oil returndevice 43 is secured in a drilled hole 44 in the head 4|, and itcommunicates with-the suction conduit 42. .This. member is formed of atube provided with a .de-

pending loop or trap portion 45 and a vertical gas intake terminal 46disposed adjacent the top portion of the header. A small oil inlet hole41 is provided in the return device at a high point in the terminal 46.This arrangement permits the gaseous products of evaporation to bewithdrawn at a high point in the header above the liquid level, whilethe oil hole 41 is disposed at a point at the liquid level where itpermits the slow passage of oil into the trap portion 45.

The -gas intake :46 is protected from direct association with therelatively violent discharge action at the duct terminals by a shield orbaiile 49. This member is in the form of an inverted casingv havingmarginal flanges 5| which engage under the projecting duct extremitiesand thus serve as securing means. The ends of the bafile 49 abut theheads 39 and 4|. This arrangement permits the ebullient fluid emergingfrom the ducts to expend its energy in the upper chamber 52, thusformed, while the liquid in the inner or quiet chamber 53 will beretained in a relatively tranquil state, so that oil separation andsubsequent removal by the device 43 may be efii- 0 Holes 54 are formedin the top of the battle to permit the passage of gas from the chamber52 to'the upper portion of chamber 53, whence it is directed into thegas intake 46.

' In Figs. 7-10 the invention is utilized in an evaporator which isformed for the purpose of producing ice cubes in large quantities. Theevaporator includes a large ice tray housing formed of a plurality ofsuperimposed ice tray containers or sleeves 56. Beneath each sleeve orshelf portion of this structure, a duct is secured in intimate thermalcontact, the ducts being indicated by the numerals 51, 58, 59, 60, 6|,and 62. The ducts are formed with central loops 51a, 58a, etc.', whichIproject beyond the rear of the sleeves 56, and which are eachvertically drilled through as indicated by' the numeral 63. A plate orcap 641s secured to the rear of the sleeve structure and it is formedwith spaced slots 55 through which the central loops project.

A feed tube 65 is threaded through the loops and soldered in position,and it contains ports 66 which may 'be identical in disposal andfunction to the ports of the tube 30 of Fig. 1. The ducts are eachsymmetrically disposed from the feed portion thereof, and they terminatein external legs 51b, 5827, etc., which extend about the terminaldisposal of successive ducts.

The remaining end,

' perature differential.

the assembled sleeves and enter a suction header 6! at equally spacedintervals. The header may be formed in a similar manner to the header ofIt will be observed that each sleeve is in intimate thermal contact withapproximately the same lineal length of duct tubing as a result of Theuppermost sleeves, for example, contacts four legs of duct tubing,compared to the six legs in contact with the bottom tray (compare Figs.7 and 9). However, the former is supplied with twelve compensatinglengths of vertical tubing formed by the duct extremities, while thelatter is furnished with but two.

Although the described similar lineal characteristics of the coils arenot an absolute necessity in a structure of this type, it is to bepreferred, since it provides equal freezing characteristics for the icetrays, and simplifies the feed tube port structure to the extent thatthe ports thereof may be all of equal size.

In commercial evaporator coils used for air conditioning and the like, acomparatively higher several useful results. The coils of Figs. 11 and14 are identical in structure, with the exception of the feedconnection, and they consist of a plurality of serpentine ducts 10disposed in parallelism and having outlet extremities ll entering alarge header 12. The usual cross fin structures 13 are applied to theducts.

The header 12 receives the upper extremities of the ducts, and it isprovided with a head 14 which is tapped to receive a suction conduit 15,and which is formed with an axial projection 15 tapped to receive avertical gas inlet pipe 11. The pipe projects vertically through anopening 18 in the header wall, which is sealed with a cap 19. A smallhole 8| is drilled in the pipe 11 to provide an oil return passage.

In Figs. 11-13, the lower terminals 82 of the ducts are closed by caps83, and each duct is drilled to receive a feed tube 84 which leads tothe refrigerant control means (not shown). Ports 85, drilled in the feedtube, communicate with each duct (Fig. 12).

In Figs. 14 and 15, pairs of lower terminals 82 are connected by loops86 which are drilled to receive the feed tube 81. Thus each pair ofducts receives refrigerant from a common supply. This disposal may bevaried according to the dimensional or thermal characteristics of thecoil, as obviously any desired group of ducts may be sup- I plied inthis manner.

In the operation of the coils, it is usual to place them in an air ductor tunnel, with the air flowing-parallel to the fins thereon. As is wellunderstood in the art, a preferential heat' exchange condition occursunder these circumstances in which the heat transfer from the ducts tothe moving air stream progressively diminishes in succeeding ducts asthe result of reduction of air velocity and the progressive reduction oftem- The first duct to the left in Fig, 14, for example, may easily bearthirty per cent of the total heat transfer load of the coil, while thelast duct may perform but five per cent of the work.

With the feed and header system of the present invention, each duct iscontinuously retained in flooded condition, even though the demands ofeach duct are incommensurate with the feed characteristics of the feedtube ports; that is, the first duct may not receive enough refrigerantfrom its port, While the last duct may receive an excess supply. In thisevent, the excess refrigerant is introduced into the header 12 to act asa supply or reserve for gravitationally feeding the ducts in which morerefrigerant is demanded.

From the foregoing it will be appreciated that the valve or otherrefrigerant control means may be set to provide for the partial floodingof the header 12, whereupon the duct supply system will be automaticallyself-compensating without further attention or recourse to the intricateindividual duct controls which have previously been deemed necessary.

I claim:

1. An evaporator comprising a suction header, an ice tray housing memberdisposed beneath said header, horizontal shelves in the housing, alooped duct beneath each shelf having terminal portions extending upwardinto said header, and a feed tube extending transversely through centralportions of all of said ducts, said tube being formed with a pluralityof outlet ports, each port being disposed in a portion of said tubewithin a duct.

2. An evaporator comprising a suction header, an ice tray housing memberdisposed beneath said header, a shelf in said member,. a plurality ofducts extending about the exterior of said memher and having terminalportions communicating with the header, a duct secured beneath saidshelf and having a central loop portion projecting beyond one end ofsaid member and terminal portions communicating with the header, and afeed tube extending transversely through the loop of said last namedduct and central portions of the remaining ducts, said tube being formedwith a plurality of outlet ports, each outlet port being disposed in a.portion of said tube within a duct.

3. An evaporator comprising a suction header, a plurality ofsuperimposed sleeves forming an ice tray housing, a duct disposedbeneath each sleeve and having a central looped portion projectingbeyond one end of the overlying sleeve, each duct having terminalportions bent upward against the sides of overlying sleeves and enteringsaid header, and a feed tube extending transversely through the loopedportions of said duct, said tube being formed with a plurality of outletports, each outlet port being disposed in a portion of said tube withina duct.

4. An evaporator comprising a suction header, an ice tray housingdisposed beneath said header and having a plurality of horizontalshelves forming ice tray compartments therein, a looped duct formed oftubing and disposed beneath each shelf, said ducts being ofprogressively greater lineal length from the lower to the upper of saidshelves, each duct having a pair of terminal portions extending upwardagainst sides of said housing, said pairs of terminal portionsprogressively contacting a greater number of ice tray compartments fromthe uppermost to the lowermost duct, whereby each compartment iscontacted by a substantially equal lineal length of duct tubing, and afeed tube extending transversely through central portions of all of saidducts, said tube being formed with a plurality of outlet ports, eachoutlet port being disposed in a portion of said tube within a duct.

5. An evaporator comprising a suction header, a plurality of spacedsleeves each forming an ice tray compartment disposed in superimposedrelation beneath said header, a plurality of spaced continuousrefrigerant ducts depending from said header, said ducts each havingterminal portions connected to said header, each of said ducts extendingdownward in contact with the side walls of a sleeve and into the spacebetween a pair of adjacent sleeves and in contact with the surfaces ofsaid sleeves, the length of each duct being substantially equal to thelength of the other ducts, the length of each duct disposed between anypair of adjacent sleeves plus the length of all ducts in contact withthe side walls of any sleeve with a plurality of vertically spacedslots, said housing being formed with a plurality of spaced shelvesdisposed adjacent to said slots, a duct secured beneath each shelf andhaving terminal portions extending upward into said ,header, each ducthaving a central loop portion projecting through a slot in the back'wall of the cabinet, and a feed tube extending transversely through theloop portions of said ducts, said tube being formed with a plurality ofoutlet ports, each outlet port being disposed in a portion of said tubewithin a duct.

8. An evaporator comprising a suction header, a plurality of ducts oftubular formation communicating With said header, said ducts being eachformed with transversely aligned holes,an

independent feed tube passed through the holes of the ducts, means forsealing the tube to each of the ducts at the points of entry and exitthrough the holes, and a plurality of ports in said 'tube, each of saidports being disposed to lie within the confines of the bore of one ofthe ducts.

9. An evaporator comprising a suction header, a plurality of ducts oftubular formation having terminal portions communicating with saidheader, said ducts being each formed with transversely aligned holes atsubstantially central points therein relative to the terminal portions,an independent feed tube passed through the holes of the ducts, meansfor sealing the tube to each of the ducts at the points of entry andexit through the holes, and a plurality of ports in said tube, each ofsaid ports being disposed to lie within the confines of the bore of oneof the ducts.

10. An evaporator comprising a suction header, an ice tray housingmember disposed beneath said header, a plurality of ducts extendingabout the exterior of said member and having terminal portionscommunicating with the header, each duct being formed with transverselyaligned holes located in the portions of the ducts which are beneathsaid member, a feed tube passed through the holes of the ducts, meansfor sealing the tube to each of the ducts at the points of entry andexit through the holes thereof, and a plurality of ports in said tube,each of said ports being disposed to lie within the confines of'the boreof one of the ducts.

11. An evaporator comprising a suction header, I

communicating with said header and depending v therefrom, said ductsbeing each formed with transversely aligned holes, a feed tube passedthrough the holes of the ducts, means for sealing the tube to each ofthe ducts at the points of entry and exit through the holes thereof, aplurality of ports in said tube, each of said ports being disposed tolie within the confines of the bore of one of the ducts, said headerbeing disposed horizontally to provide a liquid reservoir incommunication with all of the terminal portions of the ducts.

12. An evaporator comprising a suction header,

versely aligned holes, a feed tube passed through 'the holes of theducts, means for sealing the tube to each of the ducts at the points ofentry and exit through the holes thereof, a plurality of ports in thetube, each of said ports being disposed to lie within the confines ofthe bore of one of the ducts, said ports being proportioned so that thesum of their areas is less than the ef- 1o fective cross sectional areaof the tube.

LAWRENCE C. SMITH.

